The present invention relates to a system for delivering a self-expanding stent to a body vessel that requires reinforcement in situations where the vessel may have become occluded, or where the vessel may have lost its structural strength and is tending to collapse. More specifically, the invention is related to the catheter technology set forth in application Ser. No. 13/118,325, published as U.S. 2011/0295354 and which is incorporated herein in its entirety. In prior art inventions such as the cited application, a catheter system may be provided that requires two tubes located in a catheter handle to be axially aligned with each other, and to be capable of moving axially in relation to each other. Further, one tube may be configured to slide axially within the handle of the catheter and, therefore, to move axially in relation to the other tube which may be fixed. This movable tube may be operably connected to a stent advancement member. The stent advancement member may be shaped to have forward pointing barbed elements, capable of engaging with a self-expanding stent in a compressed condition, and forcing the stent distally out of a sheath in a series of oscillating movements that include a series of distal movements.
Significantly, such axially aligned tubes may also be configured to receive a guidewire that extends axially down the bore of both tubes. It is frequently desirable that the distal end of the guidewire may be inserted into the tubes from the proximal end of the catheter, and also that the proximal end of the guidewire may be inserted into the tubes from the distal end of the catheter. Yet a problem arises in the prior art because the junction between the two axially aligned tubes typically presents a geometry in which the end of the guidewire, either the distal tip or the proximal end, may become snagged or blocked by engagement with one of the tube ends during insertion.
Accordingly, there is a need in the prior art for a system of axially aligned tubes, capable of axial movement in relation to each other, that may be conveniently and inexpensively installed in a catheter that addresses the needs in the prior art. The present invention addresses these and other needs.